Field of Invention
The objective of present invention relates to new 1-phenyl-1- (N-alkylamino)-2-nitropropanes of the general structural formula (1) and their synthesis from l-phenyl-2-nitropropene of the structural formula (2) by using primary and secondary alkyl amines.

Where R -alkyl and R'=H or alkyl
Background of invention
The nitro group is a powerful electron-withdrawing substituent and this property dominates the chemistry of all molecules containing this functional group. For example, nitro alkenes, being markedly electron-deficient, undergo addition reactions with different nucleophiles. The nitro group is particularly versatile in organic synthesis since it may be transformed into a legion of diverse functionality. The versatility of the nitroalkenes as reflected in diverse chemical reactions and synthesis has been the subject of research and development and the trend till 1980 has been extensively reviewed in Tetrahedron, Vol. 37, pp.1453-1480 (1981). Similar report on the versatility of 2-nitro-3-(pivaloyloxy) propene is described in J. Chem. Soc. chem.Commun., pp. 73-74 as a reagent for multicomponent coupling reactions. Some key intermediates from 2-nitro-3-(pivaloyloxy) propene were also described in Chem. Rev., Vol. 86, pp.751-762 (1986) by coupling with different nucleophiles.
Tetrahedron Lett., Vol. 22, pp. 3223-3226(1981) describes the nitroallylation chemistry as a proven versatile method in organic synthesis to produce alkylated products of indoles, 1-lithionaphthalene and 2-lithio-2-phenyl-l, 3-dithiane.

Helv. Chim. Acta., Vol. 67, pp. 261-283(1984) also centers on the nitroallylation chemistry and describes the method to prepare nitrodiolefin from vinylaziridine and p-nitrostyrene.
J. Org. Chem., Vol 50, pp. 1182-1186(1985) describes the synthetic methods to produce l-(2,5-dimethoxyphenyl)-2-nitropropene, 2,5-dimethoxybenzonitrile, 3-(2,5-dimethoxyphenyl)-5-methyl-l, 2,4-oxadiazole by condensation of 2,5-dimethoxy-benzaldehyde with nitroethane and ammonium acetate in glacial acetic acid.
Tetrahedron Lett., Vol. 30, No. 6, pp. 731 -734(1989)describes diastereoselective conjugate addition of benzylalkoxide anion to nitroolefins to give anti p-nitroethers. Nitroolefins are shown to be effective Michael acceptors produce nitroalkane intermediates that are converted into oxygen and nitrogen heterocycles.
J. Am. Chem. Soc, Vol. 74, pp. 1700-1703(1952) and Synthesis, Issue 10, p. 841(1982), describes the use of nitroolefins as Michael acceptors, in the synthesis of spirobicyclic heterocycles from lithium enolate of cycloalkanones with nitroethene and commercially available p-nitrostyrene under aprotic conditions in THF at -78°C to form in situ a nitronate followed by addition of formaldehyde.
Tetrahedron Lett, Vol. 33, No. 25, pp. 3691-3694(1992) reports addition of formaldehydedimethylhydrazone to simple nitro-olefins in the absence of base to give rise to p-nitrodimethylhydrazones in high yield.
J. Org. Chem., Vol. 59, pp. 3681-3682 (1994) describes the reaction of aryl aldehydes with nitroethane in presence of ammonium acetate in acetic acid followed by bromination in dichloroethane to give dibromo compounds.
In Tetrahedron Lett., Vol. 40, pp. 4177-4180(1999) preparation of substituted tetrahydroindole like 1 -benzyl-3-phenyl-1 H-indole(70%yield) from cyclohexylidinebenzylimine and £ra«s-P-nitrostyrene with subsequent dehydrogenation is described .

J. Chem. Soc, Perkin Trans I, pp. 223-228 (1997) describe the Michael addition of 2-ethoxy-3-morpholinobuta-l, 3-diene to 1-nitrocyclohexene in chloroform to give a mixture of cis and trans stereoisomers. The same dieneamine on reaction with p-nitrostyrene furnished a mixture of acyclic and cyclic products in the ratio of 3:1
respectively.
The Michael reaction of chiral 3-substituted secondary enaminoesters with 2-substituted nitroethylenes leads to (Z) adducts, with good diastereoselectivity as described in J. Org. Chem., Vol. 65, No. 15, pp. 4593-4600(2000).
Organic Lett., Vol. 5, No. 14, pp. 2559-256l(2003)reported the regio-, stereo-and enantioselective direct Michael addition of a-hydroxyketones to p-arylnitroolefms catalysed by (S,S)-N-/-propyl-2,2'-bipyrrolidine (iPBP)
Thus it is noticed from the literature that l-phenyl-2-nitropropene has not been used in Michael addition reactions using amines. Hence it is proposed in this work to prepare new 1-phenyl-1- (N-alkylamino)-2-nitropropanes from 1-phenylnitropropenes using primary and secondary alkylamines.
The present invention relates to the compounds of the structural formula (1) namely 1-phenyl-1- (N-alkylamino)-2-nitropropanes

Where R =alkyl and R'=H or alkyl. In a preferred embodiment of the present invention, process for the preparation of the compounds of the structural formula (1) in which the compound of the formula (2)


namely l-phenyl-2-nitropropenes are subjected to treatment with primary or secondary alkyl amines in the solvent medium to obtain product in pure form.
Specifically, the object of the present invention is to provide a new process for 1-phenyl-1- (N-alkylamino)-2-nitropropanes by treatment of primary/secondary alkylamines with phenylnitropropenes in stoichiometric ratio by utilizing the Micheal addition reactions.

In all the cases the starting material, phenylnitropropene is prepared by condensation reaction between benzaldehyde and nitroethane and by recrystallising the product from ethanol.

Objectives of the invention
The main objective of the present invention is to provide a new 1-phenyl-1-(N-alkylamino)-2-nitropropanes of the structural formula (1)
Another objective of the present invention is to provide a novel process for the synthesis of compounds of the structural formula (1).
Another objective of the present invention is to provide a novel process for the synthesis of compounds of the structural formula (1) from l-phenyl-2-nitropropenes (formula-2) by treatment with primary /secondary alkyl amines.

Yet another objective of the present invention is to provide a process to synthesise compounds of formula (1) in 70-80% yield as the first crop.
Still another objective of the present invention is to provide process to isolate compounds of formula (1) in chemically pure form (99-100%)
DETAILED DESCRIPTION OF THE INVENTION
Accordingly, the present invention relates to new 1-phenyl-l-(N-alkyl amino)-2-nitropropanes.
According to another embodiment of the present invention, there is provided a new process for the preparation of 1-phenyl-l-(N-alkylamino)-2-nitropropanes from 1-phenyl-2-nitropropene by treatment with primary/secondary alkylamines which comprises,
1.adding of 1-phenyl-2-nitropropene to the organic solvent
2.adding of amine to the step (1) solution
3.stirring the resulting reaction mass of step (2) for a period of 7 h to 120 hrs
4.concentrating the reaction mass to obtain the reaction residue
5.adding of solvent to dissolve the residue and cooling to
-30°C to +25°C
6.filtering the resulting mass of step (5) to obtain pure 1-phenyl-l-(N-alkylamino)-2-
nitropropanes.
7.obtaining the physical and spectroscopic data (IR,1H NMR,13C NMR and mass
spectra)to confirm the structure of the product.
l-Phenyl-2-nitropropene used in step (1) is selected from nitroolefins. Solvent used in step (1) may be selected from organic solvents preferably tetrahydrofuran. The amine used in step- (2) is selected from substituted and unsubstituted primary or secondary alkylamines. Quantity of amine used in step- (2) is 0.2 to2.0 eq to that of nitroolefin, preferably 1 eq. Stirring the reaction mass in step(3) is

carried out for 7h to 120h preferably 72h.Concentrating the reaction mass to obtain residue in step(4) is effected at atmospheric pressure or under vacuum preferred one being under vacuum.
The solvent used in step (5) is selected from group of organic solvents preferred one being methanol. Cooling of the mass is effected at a temperature range of -30°C to +25°C preferably 0-5°C.
The details of the invention are given in the examples given below which are provided solely to illustrate the invention and therefore should not be construed to limit the scope of the invention.
Example: 1
Preparation of l-phenyl-l- (N, N-dibenzylamino)-2-nitropropane
In a single-necked 100 mL round-bottom flask, l-phenyl-2-nitropropene (5g, 0.03 mol) and N, N-dibenzylamine (6g? 0.03 mol) were dissolved in 25 mL of THF and the reaction mixture was stirred for 3 days. Upon the completion of the reaction as indicated by GC/HPLC, the reaction mixture was concentrated under reduced pressure to remove the solvent. The thick brown residue was purified in methanol.
Purity of 1 -phenyl- 1-(N, N-dibenzylamino)-2-nitropropane
by HPLC : 99.0%
Yield : 78% (8.7g)
mp : 140-142 °C
Spectroscopic interpretation
The structure of 1 -phenyl-1 -(N, N-dibenzylamino)-2-nitropropane was confirmed with the help of the spectroscopic data.

a) IR (cm1) (KBr)
Aromatic C-H str. 3059, aliphatic OH str. 2930, benzenoid bands 1603 and 1493, asymmetric and symmetric str. of-N02 group 1547 and 1356, ON str. 1250, C-H oop bending of mono-substituted benzene ring 748, 704.
b) *H NMR (CDC13, 200 MHz) (5H)
Hb Hb
1.97 (3H, d, CH3-CH-N02), 3.23 (2H,d, Ph-^N-^Ph), 3.94 (2H,d,
Ha Ha Ha Ha
?h~m* Hb Ph>> 434 <1H' d> C6H5-CH-CH-N02), 5.48 (1H, m, C6H5-CH~CH-
N02), 7.40-7.55 (15H, m, aromatic protons).
Ha and Hb may be arising due to the quadrepole effect of nitrogen.
c) 13C NMR (d6-DMSO, 200 MHz) (8C)
17.02 (CH3-CH-N02), 52.71 (-N-CH2-C6H5), 63.31
(C6H5-CH-CH-N02), 82.52 (C6H5-CH-CH-N02), 125.71-136.92 (aromatic carbons).
d) Mass spectrum (EI)
M+' at m/z 360 (absent), [M-^C-CH-NO)]* at m/z 302(19),
[M-(^C-CH-N92 )]+ at m/z 286( 14), c6H5^N^QH5at m/z 196( 100), C()H-CH-CHCNC°H2 at m/z 164(69), C6H5NH2 at m/z 107(26).
Example: 2 Preparation of l-phenyl-l-(N-benzyI-N-methylamino)-2-nitropropane:

In a single-necked 100 mL round-bottom flask, 1-phenyl-2-nitropropene (5g, 0.03 mol) and N-methylbenzylamine (3.63g, 0.03 mol) were dissolved in 25 mL of THF and the reaction mixture was stirred for 3 days. Upon the completion of the reaction as indicated by GC/HPLC, the reaction mixture was concentrated under reduced pressure to remove the solvent. The thick brown residue was purified in methanol.
Purity of 1-phenyl-l-(N-benzyl-N-methylamino)-2-nitropropane
by HPLC : 99.0%
Yield : 70% (6.2g)
mp :118-120°C
Spectroscopic interpretation:
The structure of l-phenyl-l-[N-benzyl-N-methylamino)]-2-nitropropane was confirmed with the help of the spectroscopic data.
a) IR (cm1) (KBr)
Aromatic C-Hstr. 3024, aliphatic C-Hstr. 2955, benzenoid bands 1560 and 1490, asymmetric and symmetric str. of-N02 group 1545 and 1352, ON str.1296, C-H oop bending of mono-substituted benzene ring 752, 706.
b) XH NMR (CDC13, 200 MHz) (8H)
1.39 (3H, d, CH3-CH-N02), 2.15 (3H,s, CH3-N-CH2-C6H5), 3.28
Hb Hb
(1H, d, H>c~N~rCA), 3.64 (1H, d, H3C-N-?-C6H5)9 4 23 ^ ^ Q^-CH-^H-
Ha Ha
N02), 5.40 (lH,m, CH3CHN02), 7.19-7.50 (10H, m, aromatic protons). Ha and Hbmay be arising due to the quadrepole effect of nitrogen.

c) 13C NMR (CDCI3, 200 MHz) (5C)
15.54 (CH3-CH-NO2), 35.16 (CH3-N-CH2-C6H5), 56.60 (-N-CH2-C6H5), 69.08 (CH3-N-CH-C6H5), 81.83 (CH3-CH-N02), 125.27-136.68 (aromatic carbons).
d) Mass spectrum (CI, methanol)
[M+H] at m/z 285(46), [C6H5CONH(CH3)(CH2C6H5)] at m/z 226(35),
[c6H5CHN(CH3)(CH2c6H5)]atm/z210(i00)Jc6H5-cWHCNO2] at m/z 164(22),
CH3
[C6H5-NH-CH3]+' at m/z 107(26).
Example: 3
Preparation of l-phenyl-l-[N-2-(4'-methoxyphenyl)-2-(l "-hydroxy cyclo hexyl) ethyl amino]-2-nitropropane:
In a single-necked 100 mL round-bottom flask, 1-phenyl-2-nitropropene (5g, 0.03 mol) and 2-(4'-Methoxyphenyl)-2-(r-hydroxycyclohexyl) ethylamine (6g, 0.03 mol) were dissolved in 25 mL of THF and the reaction mixture was stirred for 3 days. Upon the completion of the reaction as indicated by GC/HPLC, the reaction mixture was concentrated under reduced pressure to remove the solvent. The thick brown residue was purified in methanol (10ml).
Purity of l-phenyl-l-[N-2-(4'-methoxy-phenyl)-2-(l"- hydroxyl cyclohexyl) ethylamino] -2-nitropropane
by HPLC : 99.9%
Yield :80%(10g)
mp : 113-116 °C

Spectroscopic interpretation:
The structure of l-phenyl-l-[N-2-(4'-methoxy-phenyl)-2-(l"-hydroxyl-cyclohexyl) ethylamino]-2-nitropropane was confirmed with the help of the spectroscopic data.
a) IR (cm"1) (KBr)
N-H str. 3211, OH str. of tert-alcohol 2932, benzenoid bands 1609 and 1582, asymmetric and symmetric str. of nitro group 1512 and 1350, ON str. 1242, C-0 str. at 1030, OH oop ofp-disubstituted benzene ring at 833.
b) !H NMR (CDC13, 300 MHz) (5H)
1.05 (3H, m, CH3-CH-NO2), 1.40-1.68 (10H, m, cyclohexyl ring protons), 1.85 (2H, m, -NHCHjCH-), 2.48 (1H, d, Ar-CH-cyclohexyl), 2.74 (1H, m, -OH), 3.60 (1H, t, NH), 3.80 (3H, s, -OCH3), 4.10 (1H, m, C6HrCH-CH-N02), 5.47 (1H, s, C6H5-CH-CH-N02), 6.80-7.44 (9H, m, aromatic protons).
c) 13C NMR (CDCI3,300 MHz) (8C)
20.56 (CH3-CH-NO2), 21.78- 45.30 (l,l,disubstituted cyclohexyl ring carbons), 53.18 (-NH-CH2-CH-), 55.21 (Ar-CH-cyclohexyl), 62.53 (C6H5-CH-CH-NO2), 74.01 (C6H4-OCH3), 80.28 (C6H5-CH-CH-N02), 113.35-161.75 (aromatic carbons).
d) Mass spectrum (CI, methanol)
[M+H]+ at m/z 413(1), [MH+-(CH3-CH2-N02)] at m/z 338(26), [MH+-(CH3-CH2-N02)-H20] at m/z 320(100).

Example: 4
Preparation of 1-phenyl-l- [N-(l-(R)-phenylethylamino)]-2-nitropropane:
In a single-necked 100 mL round-bottom flask, 1-phenyl-2-nitropropene (5g, 0.03 mol) and l-(R)-(+)-a-Phenylethylamine (3.8g 0.03 mol)) were dissolved in 25 mL of THF and the reaction mixture was stirred for 3 days. Upon the completion of the reaction as indicated by GC/HPLC, the reaction mixture was concentrated under reduced pressure to remove the solvent. The thick brown residue was purified in methanol (10ml).
Purity of l-phenyl-l-[N-(l-(R)-phenylethylamino)]-2-nitropropane
by HPLC : 99.0%
Yield : 75% (6.5g)
m p : 92-94 °C
[a]D : +143°
Spectroscopic interpretation:
The structure of l-phenyl-l-[N-(l-(R)-phenylethylamino)]-2-nitropropane was confirmed with the help of the spectroscopic data.
a) IR (cm1) (KBr)
N-H str. 3319, aromatic OH str. 3028, aliphatic OH str. 2922, benzenoid bands 1603 and 1493, asymmetric and symmetric str. of -N02 group 1551 and 1364, ON str. 1304, OH oop bending of mono-substituted benzene ring 764, 706.

b) *H NMR (CDCI3, 300 MHz) (8H)

Example: 5
Preparation of 1-phenyl-l- [N- (l-(S)-phenylethylamino)]-2-nitropropane:
In a single-necked 100 mL round-bottom flask, l-phenyl-2-nitropropene (5g, 0.03 mol) and l-(S)-(-)-a-Phenylethylamine (3.8g, 0.03 mol) were dissolved in 50 mL of THF and the reaction mixture was stirred for 3 days. Upon the completion of the reaction as indicated by GC/HPLC, the reaction mixture was concentrated under reduced pressure to remove the solvent. The thick brown residue was purified in methanol (10ml).

Purity of 1 -phenyl- l-[N-(l-(S)-phenylethylamino)]-2-nitropropane
by HPLC : 99.0%
Yield : 77% (6.7g)
m p : 93-95 °C
[a]D : -143°
Spectroscopic interpretation:
The structure of 1-phenyl-l-[N-(l-(S)-phenylethylamino)]-2-nitropropane was confirmed with the help of spectroscopic data.
a) IR (cm1) (KBr)
N-H str. 3319, aromatic OH str. 3028, aliphatic C-H str. 2922, benzenoid bands 1603 and 1493, asymmetric and symmetric str. of-N02 group 1551 and 1366, ON str. 1304, C-H oop bending of mono-substituted benzene ring 766, 706.


d) Mass spectrum (CI, methanol)
M+- at m/z 284 (absent), [M-(CH3—CH—NO2 )] at m/z 210(100), [C6H5-CH2-CH3]+' at m/z 106(44) and [C6H5-CH-CH3] at m/z 105(12).
Example: 6
Preparation of l-phenyl-l-[N«(l-(R/S)-phenylethylamino)]-2-nitropropane:
In a single-necked 100 mL round-bottom flask, 1-phenyl-2-nitropropene (5g, 0.03 mol) and l-(R/S)-(±)-a-Phenylethylamine (3.8g, 0.03 mol) were dissolved in 50 mL of THF and the reaction mixture was stirred for 3 days. Upon the completion of the reaction as indicated by GC/HPLC, the reaction mixture was concentrated under reduced pressure to remove the solvent. The thick brown residue was purified in methanol (10ml).
Purity of 1-phenyl-l- [N-(l-(R/S)-phenylethylamino)]-2-nitropropane
by HPLC : 99.0%
Yield : 70% (6g)
m p : 92-94 °C
[a]D : 0°
Spectroscopic interpretation:
The structure of 1-phenyl-l-[N-(l-(R/S)-phenylethylamino)]-2-nitropropane was confirmed with the help of the spectroscopic data.

a) IR (cm1) (KBr)
N-H str. 3319, aromatic OH str. 3028, aliphatic OH str. 2922, benzenoid bands 1600 and 1492, asymmetric and symmetric str. of-N02 group 1549 and 1364, ON str. 1304, OH oop bending of mono-substituted benzene ring 766, 702.

d) Mass spectrum (CI, methanol)
M+- at m/z 284 (absent), [M-(CH3-CH—NO2 )] at m/z 210(100), [C6H5-CH2-CH3]+- at m/z 106(51), [C6H5-CH-CH3] at m/z 105(14).
Advantages of the invention
1. A simple one-pot synthetic process for the preparation of novel Michael
products with the possibilities of having therapeutic value.
2. The products obtained in the present invention are new and hitherto not
reported in the literature.

New 1-phenyl-l-(N-alkylamino)-2-nitropropanes and process for their preparation as claimed in claimlto3 wherein stirring the reaction mass in step (iii) is carried out for 7h to 120h preferably 72h.
5. New 1-phenyl-l-(N-alkylamino)-2-nitropropanes and process for their preparation as claimed in claim lto4 wherein concentrating the reaction mass to obtain residue in step (iv) is effected at atmospheric pressure or under vacuum preferred one being under vacuum
6. New 1 -phenyl-l-(N-alkylamino)-2-nitropropanes and process for their preparation as
claimed in claim lto5 wherein the solvent used in step (v) is selected from a specific
group of organic solvents preferred one being methanol. Cooling of the mass is effected
at a temperature range of -30°C to +25°C preferably 0-5°C.
7. New 1-phenyl-l-(N-alkylamino)-2-nitropropanes and process for their preparation as
claimed in claims lto6 wherein filtration is done in step-(vi) to obtain pure 1-phenyl-1-
(N-alkylamino)-2-nitropropane as white solid.